KVM: introduce update_memslots function

Introduce update_memslots to update slot which will be update to
kvm->memslots

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index af546b7..917a287 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3546,7 +3546,7 @@
 		memslot = &slots->memslots[log->slot];
 		memslot->dirty_bitmap = dirty_bitmap;
 		memslot->nr_dirty_pages = 0;
-		slots->generation++;
+		update_memslots(slots, NULL);
 
 		old_slots = kvm->memslots;
 		rcu_assign_pointer(kvm->memslots, slots);